Systematic literature review evaluating evidence and mechanisms of action for platelet-rich plasma as an antibacterial agent.

Platelet rich plasma or PRP is a supraphysiologic concentrate of platelets derived by centrifugation and separation of whole blood components. Along with platelets and plasma, PRP contains various cell types including white blood cells (WBC)/leukocytes, both granulocytes (neutrophils, basophils, eosinophils) and agranulocytes (monocytes, lymphocytes). Researchers and clinicians have explored the application of PRP in wound healing and prevention of surgical wound infections, such as deep sternal wounds. We conducted this systematic literature review to evaluate the preclinical and clinical evidence for the antibacterial effect of PRP and its potential mechanism of action. 526 records were identified for screening. 34 unique articles were identified to be included in this literature review for data summary. Overall, the quality of the clinical trials in this review is low, and collectively qualify as Oxford level C. Based on the available clinical data, there is a clear trend towards safety of autologous PRP and potential efficacy in deep sternal wound management. The preclinical and bench data is very compelling. The application of PRP in treatment of wounds or prevention of infection with PRP is promising but there is a need for foundational bench and preclinical animal research to optimize PRP as an antibacterial agent, and to provide data to aid in the design and conduct of well-designed RCTs with adequate power to confirm antimicrobial efficacy of PRP in specific disease states and wound types.

Bitter melon juice targets molecular mechanisms underlying gemcitabine resistance in pancreatic cancer cells.

Pancreatic cancer (PanC) is one of the most lethal malignancies, and resistance towards gemcitabine, the front-line chemotherapy, is the main cause for dismal rate of survival in PanC patients; overcoming this resistance remains a major challenge to treat this deadly malignancy. Whereas several molecular mechanisms are known for gemcitabine resistance in PanC cells, altered metabolism and bioenergetics are not yet studied. Here, we compared metabolic and bioenergetic functions between gemcitabine-resistant (GR) and gemcitabine-sensitive (GS) PanC cells and underlying molecular mechanisms, together with efficacy of a natural agent bitter melon juice (BMJ). GR PanC cells showed distinct morphological features including spindle-shaped morphology and a decrease in E-cadherin expression. GR cells also showed higher ATP production with an increase in oxygen consumption rate (OCR) and extracellular acidification rate (ECAR). Molecular studies showed higher expression of glucose transporters (GLUT1 and 4) suggesting an increase in glucose uptake by GR cells. Importantly, GR cells showed a significant increase in Akt and ERK1/2 phosphorylation and their inhibition decreased cell viability, suggesting their role in survival and drug resistance of these cells. Recently, we reported strong efficacy of BMJ against a panel of GS cells in culture and nude mice, which we expanded here and found that BMJ was also effective in decreasing both Akt and ERK1/2 phosphorylation and viability of GR PanC cells. Overall, we have identified novel mechanisms of gemcitabine resistance in PanC cells which are targeted by BMJ. Considering the short survival in PanC patients, our findings could have high translational potential in controlling this deadly malignancy.

Grape seed extract targets mitochondrial electron transport chain complex III and induces oxidative and metabolic stress leading to cytoprotective autophagy and apoptotic death in human head and neck cancer cells.

Head and neck squamous cell carcinoma (HNSCC) is a major killer worldwide and innovative measures are urgently warranted to lower the morbidity and mortality caused by this malignancy. Aberrant redox and metabolic status in HNSCC cells offer a unique opportunity to specifically target cancer cells. Therefore, we investigated the efficacy of grape seed extract (GSE) to target the redox and bioenergetic alterations in HNSCC cells. GSE treatment decreased the mitochondrial electron transport chain complex III activity, increased the mitochondrial superoxide levels and depleted the levels of cellular antioxidant (glutathione), thus resulting in the loss of mitochondrial membrane potential in human HNSCC Detroit 562 and FaDu cells. Polyethylene glycol-SOD addition reversed the GSE-mediated apoptosis without restoring complex III activity. Along with redox changes, GSE inhibited the extracellular acidification rate (representing glycolysis) and oxygen consumption rate (indicating oxidative phosphorylation) leading to metabolic stress in HNSCC cells. Molecular studies revealed that GSE activated AMP-activated protein kinase (AMPK), and suppressed Akt/mTOR/4E-BP1/S6K signaling in both Detroit 562 and FaDu cells. Interestingly, GSE increased the autophagic load specifically in FaDu cells, and autophagy inhibition significantly augmented the apoptosis in these cells. Consistent with in vitro results, in vivo analyses also showed that GSE feeding in nude mice activated AMPK and induced-autophagy in FaDu xenograft tumor tissues. Overall, these findings are innovative as we for the first time showed that GSE targets ETC complex III and induces oxidative and metabolic stress, thereby, causing autophagy and apoptotic death in HNSCC cells.

A perspective on chemoprevention by resveratrol in head and neck squamous cell carcinoma.

Head and neck squamous cell carcinoma (HNSCC) accounts for around 6% of all cancers in the USA. Few of the greatest obstacles in HNSCC include development of secondary primary tumor, resistance and toxicity associated with the conventional treatments, together decreasing the overall 5-year survival rate in HNSCC patients to ≤50%. Radiation and chemotherapy are the conventional treatment options available for HNSCC patients at both early and late stage of this cancer type malignancy. Unfortunately, patients response poorly to these therapies leading to relapsed cases, which further, emphasizes the need of additional strategies for the prevention/intervention of both primary and the secondary primary tumors post-HNSCC therapy. In recent years, growing interest has focused on the use of natural products or their analogs to reduce the incidence and mortality of cancer, leading to encouraging results. Resveratrol, a component from grape skin, is one of the well-studied agents with a potential role in cancer chemoprevention and other health benefits. As an anticancer agent, resveratrol suppresses metabolic activation of pro-carcinogens to carcinogens by modulating the metabolic enzymes responsible for their activation, and induces phase II enzymes, thus, further detoxifying the effect of pro-carcinogens. Resveratrol also inhibits cell growth and induces cell death in cancer cells by targeting cell survival and cell death regulatory pathways. Growing evidence also suggest that resveratrol directly binds to DNA and RNA, activates antioxidant enzymes, prevents inflammation, and stimulates DNA damage checkpoint kinases affecting genomic integrity more specifically in malignant cells.

Grape seed extract and resveratrol prevent 4-nitroquinoline 1-oxide induced oral tumorigenesis in mice by modulating AMPK activation and associated biological responses.

Preventive measures against oral carcinogenesis are urgently warranted to lower the high morbidity and mortality associated with this malignancy worldwide. Here, we investigated the chemopreventive efficacy of grape seed extract (GSE) and resveratrol (Res) in 4-nitroquinoline-1-oxide (4NQO)-induced tongue tumorigenesis in C57BL/6 mice. Following 8 weeks of 4NQO exposure (100 µg/ml in drinking water), mice were fed with either control AIN-76A diet or diet containing 0.2% GSE (w/w) or 0.25% Res (w/w) for 8 subsequent weeks, while continued on 4NQO. Upon termination of the study at 16 weeks, tongue tissues were histologically evaluated for hyperplasia, dysplasia, and papillary lesions, and then analyzed for molecular targets by immunohistochemistry. GSE and Res feeding for 8 weeks, moderately decreased the incidence, but significantly prevented the multiplicity and severity of 4NQO-induced preneoplastic and neoplastic lesions, without any apparent toxicity. In tongue tissues, both 4NQO + GSE and 4NQO + Res treatment correlated with a decreased proliferation (BrdU labeling index) but increased apoptotic death (TUNEL-positive cells) as compared to the 4NQO group. Furthermore, tongue tissues from both the 4NQO + GSE and 4NQO + Res groups showed an increase in activated metabolic regulator phospho-AMPK (Thr172) and decreased autophagy flux marker p62. Together, these findings suggest that GSE and Res could effectively prevent 4NQO-induced oral tumorigenesis through modulating AMPK activation, and thereby, inhibiting proliferation and inducing apoptosis and autophagy, as mechanisms of their efficacy.

Grape seed extract efficacy against azoxymethane-induced colon tumorigenesis in A/J mice: interlinking miRNA with cytokine signaling and inflammation.

Colorectal cancer (CRC) is the second leading cause of cancer-associated deaths, suggesting that additional strategies are needed to prevent/control this malignancy. As CRC growth and progression involve a large window (10-15 years), chemopreventive intervention could be a practical/translational strategy. Azoxymethane (AOM)-induced colon tumorigenesis in mice resembles human CRC in terms of progression of ACF to polyps, adenoma, and carcinomas and associated molecular mechanisms. Accordingly, herein we investigated grape seed extract (GSE) efficacy against AOM-induced colon tumorigenesis in A/J mice. GSE was fed in diet at 0.25% or 0.5% (w/w) dose starting 2 weeks after last AOM injection for 18 or 28 weeks. Our results showed that GSE feeding significantly decreases colon tumor multiplicity and overall tumor size. In biomarker analysis, GSE showed significant antiproliferative and pro-apoptotic activities. Detailed mechanistic studies highlighted that GSE strongly modulates cytokines/interleukins and miRNA expression profiles as well as miRNA processing machinery associated with alterations in NF-κB, ß-catenin, and mitogen-activated protein kinase (MAPK) signaling. Additional studies using immunohistochemical analyses found that indeed GSE inhibits NF-κB activation and decreases the expression of its downstream targets (COX-2, iNOS, VEGF) related to inflammatory signaling, downregulates ß-catenin signaling and decreases its target gene c-myc, and reduces phosphorylated extracellular signal-regulated kinase (ERK)1/2 levels. Together, these finding suggested that inflammation, proliferation, and apoptosis are targeted by GSE to prevent CRC. In summary, this study for the first time shows alterations in the expression of miRNAs and cytokines by GSE in its efficacy against AOM-induced colon tumorigenesis in A/J mouse sporadic CRC model, supporting its translational potential in CRC chemoprevention.

Poly[3-(3, 4-dihydroxyphenyl) glyceric acid] from Comfrey exerts anti-cancer efficacy against human prostate cancer via targeting androgen receptor, cell cycle arrest and apoptosis.

The major obstacles in human prostate cancer (PCA) treatment are the development of resistance to androgen ablation therapy leading to hormone-refractory state and the toxicity associated with chemotherapeutic drugs. Thus, the identification of additional non-toxic agents that are effective against both androgen-dependent and androgen-independent PCA is needed. In the present study, we investigated the efficacy of a novel phytochemical poly[3-(3, 4-dihydroxyphenyl)glyceric acid] (p-DGA) from Caucasian species of comfrey (Symphytum caucasicum) and its synthetic derivative syn-2, 3-dihydroxy-3-(3, 4-dihydroxyphenyl) propionic acid (m-DGA) against PCA LNCaP and 22Rv1 cells. We found that both p-DGA and m-DGA suppressed the growth and induced death in PCA cells, with comparatively lesser cytotoxicity towards non-neoplastic human prostate epithelial cells. Furthermore, we also found that both p-DGA and m-DGA caused G(1) arrest in PCA cells through modulating the expression of cell cycle regulators, especially an increase in CDKIs (p21 and p27). In addition, p-DGA and m-DGA induced apoptotic death by activating caspases, and also strongly decreased AR and PSA expression. Consistent with in vitro results, our in vivo study showed that p-DGA feeding strongly inhibited 22Rv1 tumors growth by 76% and 88% at 2.5 and 5mg/kg body weight doses, respectively, without any toxicity, together with a strong decrease in PSA level in plasma; and a decrease in PCNA, AR and PSA expression but increase in p21/p27 expression and apoptosis in tumor tissues from p-DGA-fed mice. Overall, present study identifies p-DGA as a potent agent against PCA without any toxicity, and supports its clinical application.

Generation of reactive oxygen species by grape seed extract causes irreparable DNA damage leading to G2/M arrest and apoptosis selectively in head and neck squamous cell carcinoma cells.

Head and neck squamous cell carcinoma (HNSCC) accounts for 6% of all malignancies in USA and unfortunately the recurrence of secondary primary tumors and resistance against conventional treatments decrease the overall 5 year survival rate in HNSCC patients. Thus, additional approaches are needed to control HNSCC. Here, for the first time, employing human HNSCC Detroit 562 and FaDu cells as well as normal human epidermal keratinocytes, we investigate grape seed extract (GSE) efficacy and associated mechanism in both cell culture and nude mice xenografts. GSE selectively inhibited the growth and caused cell cycle arrest and apoptotic death in both Detroit 562 and FaDu cells by activating DNA damage checkpoint cascade, including ataxia telangiectasia mutated/ataxia telangiectasia-Rad3-related-checkpoint kinase 1/2-cell division cycle 25C as well as caspases 8, 9 and 3. Consistent with these results, GSE treatment resulted in a strong DNA damage and a decrease in the levels of DNA repair molecules breast cancer gene 1 and Rad51 and DNA repair foci. GSE-caused accumulation of intracellular reactive oxygen species was identified as a major mechanism of its effect for growth inhibition, DNA damage and apoptosis, which was remarkably reversed by antioxidant N-acetylcysteine. GSE feeding to nude mice decreased Detroit 562 and FaDu xenograft tumor growth by 67 and 65% (P < 0.001), respectively. In immunohistochemical analysis, xenografts from GSE-fed groups showed decreased proliferation but increased DNA damage and apoptosis. Together, these findings show that GSE targets both DNA damage and repair and provide mechanistic insights for its efficacy selectively against HNSCC both in cell culture and mouse xenograft, supporting its translational potential against HNSCC.

Mechanisms of sulfur mustard analog 2-chloroethyl ethyl sulfide-induced DNA damage in skin epidermal cells and fibroblasts.

Employing mouse skin epidermal JB6 cells and dermal fibroblasts, here we examined the mechanisms of DNA damage by 2-chloroethyl ethyl sulfide (CEES), a monofunctional analog of sulfur mustard (SM). CEES exposure caused H2A.X and p53 phosphorylation as well as p53 accumulation in both cell types, starting at 1h, that was sustained for 24h, indicating a DNA-damaging effect of CEES, which was also confirmed and quantified by alkaline comet assay. CEES exposure also induced oxidative stress and oxidative DNA damage in both cell types, measured by an increase in mitochondrial and cellular reactive oxygen species and 8-hydroxydeoxyguanosine levels, respectively. In the studies distinguishing between oxidative and direct DNA damage, 1h pretreatment with glutathione (GSH) or the antioxidant Trolox showed a decrease in CEES-induced oxidative stress and oxidative DNA damage. However, only GSH pretreatment decreased CEES-induced total DNA damage measured by comet assay, H2A.X and p53 phosphorylation, and total p53 levels. This was possibly due to the formation of GSH-CEES conjugates detected by LC-MS analysis. Together, our results show that CEES causes both direct and oxidative DNA damage, suggesting that to rescue SM-caused skin injuries, pleiotropic agents (or cocktails) are needed that could target multiple pathways of mustard skin toxicities.

Diallyl trisulfide inhibits phorbol ester-induced tumor promotion, activation of AP-1, and expression of COX-2 in mouse skin by blocking JNK and Akt signaling.

An inverse relationship exists between the consumption of garlic and the risk of certain cancers. The present study was aimed at investigating the effect of garlic constituent diallyl trisulfide (DATS) on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced cyclooxygenase-2 (COX-2) expression and tumor promotion in mouse skin and to explore the underlying molecular mechanisms. Pretreatment of mouse skin with different garlic-derived allyl sulfides showed DATS to be the most potent in suppressing TPA-induced COX-2 expression. DATS significantly attenuated the DNA binding of activator protein-1 (AP-1), one of the transcription factors that regulate COX-2 expression, in TPA-stimulated mouse skin. DATS also diminished TPA-induced expression of c-Jun and c-Fos, the principal components of AP-1, and blunted the activation of c-Jun NH(2)-terminal kinase (JNK) and Akt. Pharmacologic inhibition of JNK or Akt by SP600125 or LY294002, respectively, resulted in diminished AP-1 DNA binding, reduced levels of c-Jun and c-Fos, and inhibition of COX-2 expression in TPA-treated mouse skin. The JNK or Akt kinase assay, taking c-Jun fusion protein as a substrate, revealed that TPA induced JNK- or Akt-mediated c-Jun phosphorylation in mouse skin, which was significantly attenuated by DATS or respective pharmacologic inhibitors. Evaluation of antitumor-promoting effect of DATS on 7,12-dimethylbenz(a)anthracene-initiated and TPA-promoted mouse skin carcinogenesis showed that pretreatment with DATS significantly reduced the incidence and multiplicity of papillomas. Taken together, the inhibitory effects of DATS on TPA-induced AP-1 activation and COX-2 expression through modulation of JNK or Akt signaling may partly account for its antitumor-promoting effect on mouse skin carcinogenesis.

Kolaviron inhibits dimethyl nitrosamine-induced liver injury by suppressing COX-2 and iNOS expression via NF-kappaB and AP-1.

AIMS: Kolaviron, a bioflavonoid isolated from the seeds of Garcinia kola has been reported to possess anti-inflammatory, antioxidant, antigenotoxic and hepatoprotective activities in model systems via multiple biochemical mechanisms. The present study investigated the possible molecular mechanisms underlying the hepatoprotective effects of kolaviron. MAIN METHODS: Biomarkers of hepatic oxidative injury, histological and immunohistochemical techniques were used. In addition, the protein expression levels of cyclooxygenase (COX-2) and inducible nitric oxide synthase (iNOS) were evaluated by western blotting while DNA-binding activities of nuclear factor kappa B (NF-kappaB) and activator protein-1 (AP-1) were determined by electrophoretic mobility shift assay. KEY FINDINGS: Kolaviron administered orally at doses of 100 and 200 mg/kg for 7 days significantly lowered the activities of serum transaminases and gamma-glutamyl tranferase induced by single intraperitoneal administration of dimethyl nitrosamine (DMN) (20 mg/kg) and preserved the integrity of the hepatocytes. Also, kolaviron at both doses reduced the DMN induced elevated hepatic levels of malondialdehyde and reversed DMN mediated decrease in hepatic glutathione. The hepatoprotective effect of kolaviron was compared to that of curcumin, an established hepatoprotective agent. Kolaviron inhibited the DMN induced expression of COX-2 and iNOS. Immunohistochemical staining of rat liver verified the inhibitory effect of kolaviron on DMN-induced hepatic COX-2 expression. Furthermore, kolaviron abrogated DMN induced binding activity of NF-kappaB as well as AP-1. SIGNIFICANCE: The ability of kolaviron to inhibit COX-2 and iNOS expression through down regulation of NF-kappaB and AP-1 DNA binding activities could be a mechanism for the hepatoprotective properties of kolaviron.

Curcumin attenuates dimethylnitrosamine-induced liver injury in rats through Nrf2-mediated induction of heme oxygenase-1.

Curcumin (diferuloymethane), a yellow colouring agent present in the rhizome of Curcuma longa Linn (Zingiberaceae), has been reported to possess anti-inflammatory, antioxidant, antimutagenic and anticarcinogenic activities. Curcumin exerts its chemoprotective and chemopreventive effects via multiple mechanisms. It has been reported to induce expression of the antioxidant enzymes in various cell lines. Heme oxygenase-1 (HO-1) is an important antioxidant enzyme that plays a pivotal role in cytoprotection against noxious stimuli of both endogenous and exogenous origin. In the present study, we found that oral administration of curcumin at 200mg/kg dose for four consecutive days not only protected against dimethylnitrosamine (DMN)-induced hepatic injury, but also resulted in more than three-fold induction of HO-1 protein expression as well as activity in rat liver. Inhibition of HO-1 activity by zinc protoporphyrin-IX abrogated the hepatoprotective effect of curcumin against DMN toxicity. NF-E2-related factor 2 (Nrf2) plays a role in the cellular protection against oxidative stress through antioxidant response element (ARE)-directed induction of several phase-2 detoxifying and antioxidant enzymes including HO-1. Curcumin administration resulted in enhanced nuclear translocation and ARE-binding of Nrf2. Taken together, these findings suggest that curcumin protects against DMN-induced hepatotoxicity, at least in part, through ARE-driven induction of HO-1 expression.

Anti-inflammatory and analgesic effects of Hedychium coronarium Koen.

Successive hexane, chloroform and methanol extracts of the rhizome of Hedychium coronarium Koen. (HC) were subjected to evaluate analgesic and anti-inflammatory activities in animal model. In acetic acid-induced writhing test, the chloroform and methanol extract at doses of 400 mg/kg body weight elicited 27.23 and 40.59% inhibition of writhing reflex respectively. Both the chloroform and methanol extracts showed significant elongation of tail flick time (41.15 and 61.32% elongation respectively) at 400 mg/kg body weight. In carrageenan induced rat paw edema test, the chloroform and methanol extracts at a dose of 400 mg/kg body weight showed statistically significant (P<0.01) inhibition of paw edema by 27.46 and 32.48%, respectively at the third hour after carrageenan injection.